What is Custom LASIK? What’s the Difference? What’s the Best?
LASIK procedures underwent a bit of a branding crisis a few years ago, where different companies adopted different names that sound almost the same: Wavefront guided LASIK, wavefront optimized LASIK, and topography guided, custom wavefront LASIK. To make it worse, Visx laser trademarked the name “Customvue” wavefront LASIK, which is indeed wavefront LASIK, but is no different than the other names defined below.
Wavefront Custom LASIK Eye Surgery: How do you make sense of it all?
Before we go further, I should define the terms.
- Wavefront guided LASIK: This is a LASIK or PRK treatment that treats the nearsightedness and astigmatism AND treats the other aberrations in our visual system.
- Wavefront Optimized LASIK: This term is a bit misleading, because it’s simply a laser vision treatment that is engineered to decrease one specific aberration, called spherical aberration as much as possible. Spherical aberration is always created when treat nearsightedness, because we have to flatten the cornea to decrease the focusing power. The more nearsighted you are, the more spherical aberration that’s induced. Wavefront optimized LASIK blends the optical zone out gradually so that the aberration is minimized. All modern lasers incorporate wavefront optimized LASIK into the treatment.
- Topography guided LASIK: Topography is the measurement of the outer curvature of your cornea, the clear dome of your eye. Topography guided LASIK is also a bit of a misleading name, because there is much more than just the outer surface of your eye that is taken into account when the custom LASIK is planned for your eye. The measurements from your entire eye are taken into account when the custom LASIK planning occurs preoperatively. The front and back surface of your cornea, lens, and retina are all measured. Your tear film is measured also, which is constantly changing. Every time you blink, your wavefront LASIK measurements change slightly. In my opinion, the term “topography guided LASIK” should be eliminated, because it’s always much more than topography. Probably a marketing thing?
- Custom LASIK eye surgery: All LASIK is custom LASIK. All experienced refractive surgeons customize your treatment to you. Your prescription, age, corneal thickness, general health, eye health, visual needs, vocation, and many other factors affect your surgeon’s recommendation of a vision correction procedure. You should completely understand the recommendation, the reasons why, and make sure that your expectations are consistent with what your surgeon is telling you. We all have limitations, and I can’t stress enough how important it is to understand and agree, so you’re not disappointed.
- Customvue Wavefront: Customvue LASIK is the trademarked name of the AMO Visx laser version of wavefront LASIK. I have used multiple different lasers in my career, and all the systems share the idea that quality of vision may potentially be improved by wavefront guided LASIK. Much like a BMW, Cadillac, Audi, and Mercedes all have brakes, wheels, windshield, etc., all wavefront guided LASIK treatments are similar.
Many patients ask me about the different types of topography guided or wavefront guided LASIK excimer laser ablation. This is a fascinating topic that involves many years of research, many Ph.D.s, the Hubble space telescope, lots of astronomy and scientists. I’ll try to help you make sense of it all.
There is really just one concept that has been given many names. The concept is that in any optical system, whether it’s a camera, telescope, glasses, contacts, or our eyes, there is some portion of the light that enters the system that is imperfectly focused or has aberrations. Aberrations cause blur, glare, haloes, scatter, distortion, or other imperfections that give a less accurate image of whatever it is that you’re trying to recreate. There’s a whole discipline in physics called physiologic optics, which studies the optics in living creatures.
A cheap camera lens is more likely to give poor images than an expensive camera lens. The expensive lens is designed and machined to focus the light more perfectly and create an image with less total aberration. Telescopes must have extremely large mirrors and lenses in them to collect more light so they can image distant celestial objects whose light is extremely weak by the time it reaches the earth.
Here’s the super-cool science:
The light that comes through the earth’s atmosphere is randomly bent and distorted by the air. Air of different temperatures has different density and therefore distorts the light irregularly. Scientists have developed wavefront analysis to determine exactly how the light is distorted. Dozens or even hundreds of tiny pistons behind the mirror deform the large telescopic mirror to correct the distortion of the light and create better images of objects in out universe. Crazy huh?
This wavefront analysis was the origin of the idea that we could analyze the imperfections of the focusing of the human eye and create a laser pattern that would improve the quality of our vision. It’s a wonderful idea, yet adding wavefront guided LASIK to wavefront optimized LASIK doesn’t seem to make a difference.
In my experience, roughly 95% to 98% of the wavefront guided LASIK or PRK laser treatment consists of low-order aberrations-that is your nearsightedness and astigmatism. The remaining 2-5% of total aberrations can be measured and treated, but in most healthy patients the high-order aberrations are such a small portion of the overall amount of laser treatment that it is difficult if not impossible to determine if it helps the quality of vision. It’s been fairly conclusively shown that wavefront treatments don’t improve the percentage of people who achieve 20/20 postoperative uncorrected vision. But you can still identify the person in the photos taken with a cheap camera. Is the vision quality better with wavefront guided LASIK?
When you compare identical images from a cheap vs. expensive camera, you can tell the difference, right? Not always! And with wavefront guided LASIK, many studies have concluded that there is little or no difference between wavefront guided and wavefront optimized LASIK. (See the references below)
The name that perhaps most accurately reflects this overall concept is wavefront guided LASIK or wavefront guided PRK. This treatment happens when your LASIK surgeon treats what’s called the “low-order aberrations,” which is the nearsightedness and astigmatism. (also called sphere and cylinder). Then the “high-order aberrations” are treated. High-order aberrations are everything that’s not your nearsightedness or astigmatism. These high-order aberrations (HOA) have names like coma (which creates a sort of comet tail to a point of light), spherical aberration (which causes a halo around a point of light) trefoil, secondary astigmatism, quadrafoil, tetrafoil, and so on. Each successive aberration down the list has less and less impact on your quality of vision.
“A rose by any other name would smell as sweet…”
As in all things, marketing plays a big part in how much it’s pushed. How many times have we heard “new and improved” and been disappointed? I’m not saying wavefront guided LASIK is bogus, I’m just saying that there are more important factors in an excellent LASIK outcome. Dry eyes, mild cataract, corneal scars from contact lens infections, lid problems, floaters, can all adversely affect your vision and LASIK outcome more than the small degree of high-order aberrations present in your visual system preoperatively.
Customvue LASIK cost is generally higher by a few hundred dollars per eye. Worth it? Possibly, and it’s something you should discuss with your surgeon preoperatively.
Whether it’s called Customvue LASIK, wavefront guided LASIK, or anything other nom de guerre, the results will most likely be excellent. Modern LASIK is awesome. If you haven’t gotten LASIK already, schedule your free comprehensive exam with SharpeVision sharpe-vision.com
The studies below can serve as your reference and lead you to as many studies as you’d like to see to help you see that whether you opt for wavefront guided LASIK or wavefront optimized LASIK, you will do great!
Conclusion: Negligible difference between wavefront guided LASIK and wavefront optimized LASIK.
Conclusion: slightly worse outcomes with wavefront guided LASIK:
Reference from paid consultant, but without the actual study link.
-Dr. Matthew Sharpe